1. Field of the Invention
The present invention relates to warp knitted ware utilizing tricot, chain or other stitches to form the ground fabric of the ware into which are laid reinforcing threads such as weft threads and various filler threads which are located in the vicinity of needle loops of adjacent chain stitches.
2. Discussion of the Relevant Art
As reinforcing threads, it is particularly desirable to utilize glass or carbon fibers which provide a substantial rigidity in the direction of thread extension. Such threads are somewhat inflexible and must therefore be utilized in a substantially linear fashion, that is to say they cannot be woven together as warps or wefts. These products are usually coated with a synthetic material so that they can be utilized as planes or as laminates for the formation of synthetic shaped bodies of high rigidity.
In a known type of warp knitted goods of the prior art [see Textiltechnik 31 (1981) p. 493] only chains and lightly crossing weft threads are utilized. This arrangement gives rise to an increased rigidity in the warp direction and in the weft direction but not in the diagonal direction. It should further be noted that the weft threads are partially penetrated by the needles of the needle bed which negatively affects the stability of the material.
It has further been disclosed (U.S. Pat. No. 3,819,461) that rigid threads may be used solely in the weft direction and be held together by chain stitches. This gives rise to higher stability in the weft direction than where the weft threads cross each other. In all other directions, however, the rigidity is not satisfactory.
It is further known (U.S. Pat. No. 2,890,579) to overlay a non-woven fabric with diagonal threads or warp inserts and to hold everything together by stitch sewing. In this material also, it should be noted that the crossing threads are penetrated by the needles of the needle bed which also negatively affects their strength.
Accordingly, there is a need for a warp knitted material which has equal rigidity in all directions in order to provide the highest total rigidity possible.